1. Field of the Invention
The present invention relates to a slotting tool for use in slotting a work.
2. Description of the Related Art
A slotting tool of the related art is constructed in a manner such that a toe of a punch does not cooperate with a die to preliminarily punch out a work. The slotting tool slots the work by means of a slotting portion of the punch and the die. Slotted scrap is punched out for cutting off from the work by means of a heel portion of the punch and the die. Therefore, the slotting tool does not work from a slotting starting position in the work. In this connection, prior to slotting the work by the slotting tools of the related art, an auxiliary and extra hole must be prepared which is located in an extension line of and overlapping the slot to be formed.
In another type of slotting tool, a repeated slotting operation is performed from a hole preliminarily and previously punched for slotting. This is required because incomplete slotting scrap is left on a work at the final stage of the continuous slotting operation, notwithstanding that this type of slotting tool does not require an auxiliary and extra hole. Therefore, the extra auxiliary hole, which is located in an extension line of the slotted hole required and overlaps with the slotted hole required, must be punched at a final and terminating slotting position, prior to slotting the work by the slotting tool.
The above slotting operations of the related art are thus complicated thereby increasing the cost of the slotting operations.
Furthermore, where a second slotted hole is required near a first slotted hole and where a micro-joint portion is required on a work and formed on the work by the first slotted hole, the micro-joint portion cannot remain on the work and therefore is not formed on the work where an auxiliary and extra hole is required.
In addition, the preliminarily punched slotted holes are typically uneven thereby reducing the accuracy of the hole.